“Mr Bob Nairn, a retired transport consultant, was commissioned by the Canberra Liberals to perform this research. Without access to the report, ACT Light Rail can only comment on what the media has selected to use in its reporting,” the rail advocates said.

“The first thing that strikes us as odd, is that the costings are based on US figures. There is ample contemporary light rail construction and vehicle procurement locally, that Australian figures and costs from Gold Coast, Adelaide or Perth could easily have been obtained. So why have the Canberra Liberals and Mr Nairn used US figures? This is puzzling, especially as Mr Nairn has experience consulting to Australian light rail projects.”

FURTHER UPDATE: Simon Corbell has come out swinging in defence of his train set.

“The paper on light rail commissioned by the Canberra Liberals chooses the most expensive construction method for the project and its use discredits the entire report,” Simon said.

“The report is inaccurate, based on incorrect assumptions and does not stack up to rigorous assessment. It does not include important economic benefits from the project and uses unsound cost and construction assumptions. The paper’s author acknowledged the report assumes a construction alignment which is more expensive than constructing in the median corridor, and makes cost assumptions based only on a very few hand-selected foreign examples.

“Cost benefit analyses for transport projects are complex. The Liberals’ paper is based upon simplistic assumptions, including very limited foreign benchmarking that is not specific to Canberra and it cannot be relied upon.

“In contrast, Capital Metro’s analysis is robust and will stand up to industry standards for a project of this complexity. Our experienced economic advisers draw upon detailed and well considered inputs prepared by specialists with extensive experience on previous similar projects.

“The Liberals’ paper is based on the most expensive alignment option, a two-tracks system, one on either side of Northbourne Avenue, where the footpaths currently are. The government’s assumptions are based on the use of the median corridor because it is a more cost effective option and one which produces a better transportation outcome.

“The figures cited in the paper on benefit cost ratio and capital expenditure are completely out of the ball park. The BCR in the Liberals’ paper is less than 1.0. In contrast, work undertaken by Capital Metro and its economic advisors confirms the BCR for Capital Metro is positive and therefore delivers a positive economic return to the ACT.”